Genesis 21:31-34

Wherefore he called that place Beer-sheba; because there they sware both of them. Thus they made a covenant at Beer-sheba: then Abimelech rose up, and Phichol the chief captain of his host, and they returned into the land of the Philistines. And Abraham planted a grove in Beer-sheba, and called there on the name of the LORD, the everlasting God. And Abraham sojourned in the Philistines' land many days.